clark



G. H. CLARK.

ADJUSTMENT 0F WAVE LENGTHS.

APPLICATION FILED JAN-18,1915:

Patented Nov. 25, 1919.

A'FI'ORNEY 2 SHEETS-SHEET 1.

G. H. CLARK.

ADJUSTMENT 0F WAVE LENGTHS.

APPLICATION FILED JAN-18,17915- I Patented Nov. 25, 1919.

2 SHEETSSHEET 2.

GEecbOrY-K W Abs? UNITED STATES PATENT" its QFFICEQ GEORGE E. CLARK, WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO MARCONI WIRELESS TELEGRAPH COMPANY OF AMERICA, A CORPORATION OF NEW JERSEY.

ADJUSTMENT or wavn IlENerns.

Specification of Letters Patent. Patent ed Nov. 25, 1919.

Application filed January 18, 1915. Serial No. 2,799.

To all whom it may concern:

Be it known that I, Gnoncn H. Omen, a citizen of the United States, of Washington, District of Columbia, have invented newand useful Improvements in Adjustment of Wave Lengths, of which the followin is a specification.

y invention relates to telegraphy,telephony, or like systems in which employed is in the electro-radiant form for space systems or in the form of high frequency oscillations for conductive systems.

Heretofore in the practical and commerclal use of systems such as above referred to, it has been impossible with the prior art apparatus available to change the transmission orreception quickly and lpromptly from a settin for one wave lengt or frequency to 'a settmg for another wavelength or frequency, because involving more than a sin-' gle movement or adjustment of an apparatus, in fact involving a plurality of independent movements for tuning and adjustmg 0 erations with resulting loss of considerable time which is a serlous disadvantage and a-chief hindrance in the satisfactory operation of apparatus of this character. I

It is the object of my inventionto'provide, either at the transmitting or receiving station, or both, apparatus whereby settings for different wave lengths or frequencies be made by a sm le operation of switching mechanism which shall at'the same time insure proper or desired coupling between inductively related oscillation circuits.

To these ends I have devised the system' and apparatus hereinafter described and constituting an embodiment of my invention.

For an illustration of one of the forms my invention may take reference is to'be which:

Figure 1 is a diagrammatic view illustrating a typical transmitting apparatus to which my invention may be applied. Fig. 2 is a diagrammatic view illustrating electrical connections and cooperating sw1tching mechanism for carrying out'my invention in transmitting apparatus.

Fig. 3 is a diagrammatic view similar to Fig. 2 when used in receiving apparatus.

the energy- :may be determined by a wave meter,

Fig 1 shows a typical transmitting appa-- secondary s of thestep-up transformer has its terminals connected to. either side of the spark gap 9 which may be of the simple type indlcated or may e of the quenched gap type, or any other suitable type. The gap 9 1s in circuit with the condenseror capacity K and the variable portions of the P of the oscillation transformer,

primary the circuit PKg being here shown as a closed oscillation circuit. The open or an of the secondary S of the oscillation transformer, a variable ortion of the loading inductance L, beyond the inductive influence of the primary P, the antenna or aerial conductor A, and the earth connection E, a radiation meter M, such as a hot wire ammeter, being included for purposes of convemence. I

When it is desired to transmit energy of a certain frequency or wave length, the variable or sliding contact in the primary circuit ismoved to such point on the primary P, as for example the point 1, which will insure the primary circuit producing oscillations of the desired frequency, corresponding with wave lengthv No.1. This Igetting calculation, or otherwise. The open or'ant enna tenna circuit comprises a variable portion circuit is then attuned to this same frequency or wave length when the coupling between P and S is lodse, by adjusting the variable contacts on S or on L until the meter M gives a maximum reading. Then by making the coupling between of such character as is to be transmittingenergy having wave length No. 1 the rider or contact sliding on the loading inductance L will have to be moved to some P and S closer and employed in I new position until the wave meter in dicates but a single maximum in the resonance curve, and the adjustment is further varied-until with this single maximum in i the resonance curve the meter M indi-. cates a maximum reading for that articular coupling. And'in this connec ion the pomt 1 in the pruna-ry P may have to be varied slightly from its first setting. However, by these well-known methods the setting of the inductance L, of secondary S and of primary P are determiuedfor the wave length No. 1. Similarly for another wave length, say No. 2, thesettings will be at the points indicated by 2; the settings for a thlrd wave length by 3, and for the 4th wave length by 4:.

In all cases the necessary or desired inductance'in the antenna or open circuit for any given wave length can be so proportioned between the secondary S and the loading inductance L that the same mechanical coupling, that is, same physical or mechanical distance or relation between the primary P and secondary S can be obtained for all wave lengths. In making this ad justment of the relative amounts of ,mductance in S and L for any wave length, if the coupling is too close, the number of turns in S is reduced and the number of turns 1n L is increased, and conversely it the coupling is too loose, the number of turns L is reduced, and the number of turns In S is increased.

By my invention I provide switching mechanism, a single movement of which will transfer the movable contacts on P, S am L to the proper points for transmission of these various wave lengths while maintaining the desired or proper coupling between the primary P and the secondary S, this couplingbeing generally such as will cause a transm1ssion of maximum energy from the closed oscillation circuit to the open antenna circuit.

In Fig. 2 this same general arrangement is shown except that the prlmary p of the step-up transformer and its circuit are omitted, and there is added the switching mechanism referred to and additional variable inductances or variometers in the open and closed circuits for sake of convenience.

The points 1, 2, 3 and 4 for the four different wave lengths areindicated as in Fig. 1. From the four points 1, 2, 3 and 4 of the primary P connections are made to the four contacts P P, P and P adapted to be engaged by the switch arm P. Similarly the four points 1, 2, 3 and 4 on the secondary S are connected respectively with the four switch contacts S S S and S with which the movable switch arm S is adapted to engage. And similarly the four points 1, 2, 3 and 4 on the inductance L are connected with the four switch contacts L L, L and L with which the switch arm L is adapted to engage. Inductance L is here shown as divided into two parts, though a eater number may be employed if desired, in order that when one part of the inductance is not in use it may be cut out of circuit (or short circuited as hereinafter de-- scribed) to prevent energy consumption by which may be set at once for all wave lengths of a group, maybe employed.

And in the primary circuit an additional inductance L" may be employed if required or desired.

The switch arms P, S*, L and e are me-' chanically connected together, as by member or shaft f, which maybe provided with a hand wheel or other operating device h.

in this figure are shown two condensers or banks of condensers K, K which may be connected in parallel or in series with each other under various circumstances. Switching mechanism for changing these condenser connections comprises stationary switchcontacts i, 7', m, n, o, and the blank 11.

The two movable contacts 1' and t are mechanically connected together but insulated from each other and mechanically connected with the operating mechanism for the switches previously described, this connection causing the contacts 1' and t to be in position shown, and thereby connect the condensers K, Kin parallel with each other, for the three right hand positions of the switch P", but when the switch P engages with contact P, the contacts t, r are shifted toward the left, '1' remaining in contact with j and engaging th blank 9, while If remains in contact with n and connects the same to o, in which case the condensers K, K are in Se rice with each other in the primary circuit, the switch P being connected with the contact m. The object of this is to have less capacity in circuit for the shorter wave length or lengths so that the corresponding coiiperating inductance ofthe primary circuitwill be a substantial part of the primary P. And in reverse movement of the switch arm P the switch contacts t and r are restored to the osition shown and occupy such position or all positions of the swltch arm P? when engaging contacts P, P and P With the parts in the position illustrated in Fig. 2 the connections are such as to transmit wave length No. 3, the amount of in-' amounts.

When the switch arm D moves to the left on to contact L or contact L the upper part of the inductance L will not be in use, and it is therefore open circuited for both these positions by the withdrawal of the switch contact e'from bridging relation with contacts oand d.

While the apparatus thus far described has beentransmitting apparatus it will be understood that the same functions may be procured for receiving apparatus.

Thus in Fig. 3 Fig. 2.has been reproduced, but in place of the apparatus shown in the primary circuit of Fig. 2 receiving apparatus is shown. And what was the primary P of Fig. 2 is now in reality the secondary of an oscillation transformer which is included in circuit with the variable capacity K a variable inductance or variometer V and a wave responsive device or detector W in shunt with which is connected a telephone receiver T or other suitable instrumentality.

Here again it will be understood that for receiving on different wave lengths the operator need merely turn the hand wheel h to any of the positions, and then by varying V and K maximum response will be obtained by tuning.

In both transmitting and receiving apparatus above described, the total inductance of the primary circuit and the total inductance of the secondary circuit are simultaneously changed for the different wave lengths by a single movement of the switching apparatus, and for each of these different values of total inductance of primary circuit and of total inductance of secondary circuit, the optimum coupling is maintained without relative movement betwen the primary and secondary coils.

As well understood in this art, the coefficient of coupling between primary and secondary circuits is equal to the mutual induction divided by the square root of the product of the total inductance of the rimary circuit multiplied by thetotal in netance of the secondary circuit. By my inven.

tion the coeflicient of coupli or as generally termed, the coupling, is maintained at the same value for the different wave lengths with a given separation between the primary and secondary coils for all those wave lengths. The switching apparatus changes the total inductances of primary and secondary circuits, the connections from the switch points to the primary, secondary and inductance being to such points in them that the coupling is maintained the same for the different wave lengths.

While with my apparatus hereinbefore described the change from one wave length or frequency to another is accomplished by a single movement, as by a single actuation of the hand wheel h for a given position of the secondary S with respect to the primary P, or a given separation between them, my inventioncomprehends also the accomplishment of the same result for different relative positions of or separations between the secondary S and the' rimary P, both when such separation is c anged bymanually shifting one or the other and when such separation is changed or varied by mechanical means.

The shaft need not be rotated or actuated manual but may be actuated by a .suitable motive device electrically or otherwise controlled from a distance to cause the shaft f to partake of the proper degrees of rotation for shifting the mechanism to theplmg between them for each of a plurality.

of different oscillation frequencies, and. means common to said switches for actuat mg them 1n unison.

2. The combination with the primary and secondary of an oscillation transformer, of an inductance in circuit with one of them, switches and connections with said primary, secondary and said inductance for simultaneously procuring predetermined couplings between said primary and secondary and the requisite amount of inductance for each of a plurality of oscillation frequencies, and means common tosaid switches for actuating them in unison.

3. The combination with the primary and secondary of an oscillation transformer, of a switch for each for varying the same, the variation in one being complementary to the variation of the other for maintaining a presaid switches to move in unison.

4. The combination with the rimary and secondary windings of an oscil ation transformer, of additional inductance, switches for varying said inductance and a winding of said transformer and means causing said switches to move in unison with each other, the variations caused by said switches being complementary to each other for maintaining a redetermined cou ling for a plurality of di erent wave lengt s 5. The combination with a winding of an oscillation transformer, of an inductance in circuit therewith a switch connected with said winding and said inductance and serving to simultaneously complementarily alter the amount of each in'circuit for-maintaindetermined coupling, and means causingf nections with said. prima ing a predetermined coupling for each of a plurality of wave lengths.

6. The combination with the primary and secondary of an oscillation transformer, of switches and connections therefrom to said primary and secondary for simultaneously maintaining a predetermined coupling and adjusting both primary and secondary circuits to different wave lengths, and means common to said switches for actuating them in unlson. v 7. The combination with the primary and secondary of an oscillation transformer oecupying a predetermined position with respect to each other, of switches and connections therefrom to said primary and secondary for maintaining a predetermined coupling between them for each of a plural-..

ity of difi'erent wave lengths, and means common to said switches for actuating them in unison.

8. The combination with the primary and secondary of an oscillation transformer occupying a redetermined position with respect to eac other, of an inductance'in cir-: cuit with one of them, and switches and consecondary and said inductance for simu taneously maintaining-a predetermined coupling between the. primary and secondary circuits and ad-' justmg said circuits to difierent wave i'engths, and means common to said switches for actuating them in unison.

9. The combination with the primary and secondary of an oscillation transformer occupying a redetermined position with respect to eac other, of an lnductance in cir-' cuit with one of said transformer windings,- and switches having connections with said. inductance and with the winding in circuit therewith for simultaneously mamtaining a predetermined coupling between primary: and secondar circuits and adjusting the circuit of sai inductance to difi'erent wave;- lengths, and means common to said switches for actuating them in unison.

10. The combination with thev primary and secondary of an oscillation transformen.

inaaitt of an inductance in circuit withone of them,

a switch and connections therefrom to said primary for varying the amount of said pri mary 1n circuit, a second switch and connections therefrom to said secondary for varying the amount of said secondary in circu t, a third switch and connections therefrom to said inductance for varying theamount of said inductance in circuit, means mechani: callycoupling together said switches, said connections being so adjusted that the circuits may beset to various wavelengths by movement .of said means without changing the predetermined coupling between the circuits.'

1 11. The combination with a transformer,

12. The combination with a transformer,

of adjusting means therefor, prima secondary circuits therefor, variable -1nductance in one of said circuits, meanscommou and:

to said adjusting means and to said inductance for varying them simultaneously to vary the period of said one of said circuits while maintaining the coupling between the two circuits constant.

13. The combination with a transformer,

of adjusting means therefor, tuning means in circuit with said transformer, and means common to said tuning means and said ad-L justing means for operating them simultane-' ously to vary the wave length while maintaining a constant co-eflicient of coupling.

In testimony whereof I have hereunto afs'ubscribingf witnesses. v

. H. QLARK.

Witnesses:

Lonnnzo G. Burrs, Enos. L. MURPHY.

fixed my signature in the presence of the two 

